Diffractive optical elements for use in a projection objective for microlithography, components for polarization control within a projection optical system of a projection exposure system, etching methods for producing diffractive optical elements, the use of doubly refracting elements with sections of different doubly refracting effect distributed over their optical surface, and optical components with doubly refracting layers are known.
It is also known to use diffractive optical elements within a microlithography projection exposure system, in particular to specify an illumination setting, i.e. a defined illumination angle distribution to illuminate the reticle.